Flashcards in Grasslands Deck (16)
What is the the geographical features of Mid-latitude (temperate) grasslands?
1.A naturally treeless ecosystem.
2.Continuous cover of grass.
3.Mostly perennial grasses (come back every year)
What is the geography of grasslands like?
Grasslands are vast in extent, especially in N. America and Eurasia
What climate types to grasslands exist in?
1. Steppe (short grass steppe)
2. Humid Continental (mixed and tall grass prairies)
What are the three types of pre-settlement N. American Prairies?
short, mid, tall grass.
What climatic factor is a major influence on patterns of prairie type at this broad (continental) scale?
Grass height varies with precipitation gradient
Why are there grasslands in Illinois and Indiana instead of forest?
Because of fire
When did the Prairie Peninsula form?
It formed during the Hypsithermal Period 8000-4000 bp (before present).
What was the Hypsithermal Period like?
A warmer-drier period, bad for trees - good for grasses
How was the Prairie Peninusla maintained. What stopped this?
Maintained by Indian burning, probably combined with buffalo grazing. This stopped when Europeans entered the picture. Fire and grazing help maintain Tall Grass Prairie like in Tropical Savannas - these disturbances kill trees and favor grass.
Whats so important about Tall Grass Prairies?
They are virtually extinct. There are only 0.06% original tall grass prairies left in North America
Whats the biggest threat to tall grass prairies?
Pretty much all tall grass prairie has been converted to agriculture
Why do farmers use tall grass prairies?
They have the best soil for agriculture. Dark, fertile Mollisol soils developed under temperate grasslands. It is organic and nutrient rich
What happened to tall grass prairies after 1837.
They were replaced by grass crops like corn and wheat and pastures and hay
Where are tall grass prairie remnants sometimes found?
They are sometimes found in old cemeteries and railroads
Out of biomes in the world, what biome is most modified by humans?
Of all biomes, mid-latitude (temperate) grasslands are most heavily modified by humans